Here's my American English translation, keeping the style casual yet engaging for adult female readers:

Andrew carefully studied her face before quickly saying, "Don't worry, I'll help you look for her. You didn't see her leave, right? She must still be in the hospital. I'll check the security cameras."

Jack and Lisa offered to help, and the four split up to search.

Meanwhile, Caroline - the one they were all looking for - was standing in Tim's hospital room, desperately ...